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Forecast(3)	      User Contributed Perl Documentation	   Forecast(3)

NAME
       Statistics::Forecast - calculates a future value

DESCRIPTION
       This is a dummy Oriented	Object module that calculates a	future value
       by using	existing values. The new value is calculated by	using linear
       regression.

SYNOPSIS
	  use Statistics::Forecast;

       Create forecast object

	  my $FCAST = Statistics::Forecast->new("My Forecast Name");

       Add data

	  $FCAST->{DataX} = \@Array_X;
	  $FCAST->{DataY} = \@Array_Y;
	  $FCAST->{NextX} = $NextX;

       Calculate the result

	  $FCAST->calc;

       Get the result

	  my $Result_Forecast =	$FCAST->{ForecastY);

INTERNALS
       The equation for	Forecast is:

	  a+bx,	where 'x' is the predicted value and
	      _	   _
	  a = y	+ bx

	  b = sum((x+x)(y-y))/sum(x-x)**2

METHODS
       new Receives a forecast name, only to remember and returns the blessed
	   data	structure as a Statistics::Forecast object.

	    my $FCAST =	Statistics::Forecast->new("My Forecast");

       calc
	   Calculate and return	the forecast value.

	    $FCAST->calc;

       dump
	   Prints data for debuging propose.

	    $FCAST->dump;

       SumX
	   Returns the sum of X	values.

	    my $SumOfX = $FCAST->{SumX};

       SumY
	   Returns the sum of Y	values.

	    my $SumOfY = $FCAST->{SumY};

       SumXX
	   Returns the sum of X**2 values.

	    my $SumOfXX	= $FCAST->{SumXX};

       SumXY
	   Returns the sum of X	* Y values.

	    my $SumOfXY	= $FCAST->{SumXY};

       AvgX
	   Returns the average of X values.

	    my $AvgX = $FCAST->{AvgX};

       AvgY
	   Returns the average of Y values.

	    my $AvgY = $FCAST->{AvgY};

       N   Return the number of	X values.

	    my $N = $FCAST->{N};

EXAMPLE
	  use Statistics::Forecast;

	  my @Y	= (1,3,7,12);
	  my @X	= (1,2,3,4);

	  my $FCAST = Statistics::Forecast->new("My Forecast");

	  $FCAST->{DataX} = \@X;
	  $FCAST->{DataY} = \@Y;
	  $FCAST->{NextX} = 8;
	  $FCAST->calc;

	  print	"The Forecast ", $FCAST->{ForecastName};
	  print	" has the forecast value: ", $FCAST->{ForecastY}, "\n";

AUTHOR
       This module was developed by Alex Falcao	(alexjfalcao@hotmail.com)

STATUS OF THE MODULE
       This is the first version and calculates	forecast value.

VERSION
       0.3

COPYRIGHT
       This module is released for free	public use under a GPL license.

perl v5.24.1			  2007-03-06			   Forecast(3)

NAME | DESCRIPTION | SYNOPSIS | INTERNALS | METHODS | EXAMPLE | AUTHOR | STATUS OF THE MODULE | VERSION | COPYRIGHT

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